U.S. Pat. No. 5,858,525 discloses a high-pressure gasket comprising a major proportion of clay mineral such as talc and a minor proportion of a hard material powder such as silica, alumina or zircon. U.S. Pat. No. 6,338,754 discloses a high-pressure gasket comprising a major proportion of clay mineral such as talc and a minor proportion of garnet, with sodium silicate binder.
United States patent application publication number 2012/0098213 discloses gasket material comprising 75 to 90 wt. % inorganic filler material, 5 to 20 wt. % inorganic fibre material and 1 to 5 wt. % organic binder material. The inorganic filler material may be hydrophobic material such as talc, which is a platy material that orients itself in layers during the gasket material forming process to provide good sealant properties. Other examples of filler material include mica and boron nitride, and the filler material is preferably sub-micron powder having particle size of 0.2 to 1.5 microns. The fibre material may be silicic acid, kaolin, blends of silica and alumina, alkaline earth silicates known as glass wool, and may have a length of 1 to 6 mm and a diameter of 3 to 12 microns.